There were question marks over whether Mahrez would be in the right state of mind to play the match at Wembley, but the former Leicester man started and netted the winner in the first half.
Srivaddhanaprabha tragically passed away on Saturday evening after his helicopter crashed outside the King Power Stadium.
Speaking to Sky Sports following Manchester City’s victory in London, Mahrez opened up on a tough 48 hours and said that his goal celebration was dedicated to the former Leicester owner.
“To be honest it has been very, very difficult for me,” the Algerian said.
“It is not easy, the boss was very special to me. I spent four-and-a-half years there and I have many special memories with him. He was such a good person, such good human so I am very, very sad.
“That is why when I scored, I put my hands up in the sky for him. He did a lot for me and for Leicester. It is difficult to speak about it because it is very sad.”
Tributes flooded in for Srivaddhanaprabha on Monday, with the Leicester City players meeting the ex-owner’s family in an emotional ceremony at the King Power on Monday.
“He was like a dad to us. He was very, very special, believe me,” he continued.
“He was such a good person, a big heart and it was heartbreaking and shocking for me to hear this news and of course with the other people who died with him with him it is a difficult situation.
“I'm with Leicester and with the family of the victim because it is not an easy situation.”
When asked if it was difficult for him to play in such an important match for City on Monday, Mahrez said:
“I always wanted to play. He would have wanted me to play. He was very passionate about football and it was difficult but I kept thinking about him.
“It was difficult to sleep as well after that. But it is part of life. It was difficult.”
Leicester have announced that there will be a book of condolence at the King Power to be shared with Srivaddhanaprabha’s family on Tuesday morning.